Information technology and the computer industry are highly developed now. People rely heavily on computer systems. Therefore, computer servers with high calculation capacity and high stability are important for computer systems. Due to increasingly reduced office space, area occupied by computer servers must also be reduced. Since computer servers maintain a high degree of stability to serve users, and the space occupied by one computer server is usually greater than or equal to that of a desktop computer. The management of computer servers is difficult and space utilization is tightened. Some normal companies have 2 or 3 computer servers, while some others may have more than a thousand computer servers. Computer server management and space utilization become more critical in companies with more computer servers.
A 1U computer server assembled on a standard 1U server rack is the mainstream computer server arrangement. Each standard layer of the rack is about 1.75 inches (about 4.5 centimeters), so that the 1U server and the rack effectively conserve occupational space of the computer servers. Moreover, the 1U servers and racks are more efficiently controlled because the 1U servers and racks can be centrally managed and easily stacked. Normally, hardware used in the 1U server is provided with a smaller size and lower height to fit the thickness limitation of 1.75 inches. A server system is convenient to user for seeking or storing data because the server rack usually provides numerous hard disks to store data therein. Especially, the hard disks on the server racks are convenient to data exchange, repair and installation because each hard disk is installed in a removable module and the removable module is installed in the server rack.
The dimensions of the server rack and the dimension of the removable module limit the quantity of conventional removable hard disk modules which can be installed in one server rack. That is to say, due to the width and height limitation, some residual space of the server rack cannot be utilized for hard disk installation. Generally, the horizontal width of the server rack is wider than the total horizontal width of four horizontal hard disks. However, for firmly installing the hard disk in the removable module and on the server rack to pass environment tests, e.g. drop test, vibration test, and shock test, to ensure the quality and life span of the server system, a sliding mechanism of a conventional removable module is coupled to a corresponding sliding mechanism of a fixing device fixed in the server rack. The corresponding sliding mechanism and the sliding mechanisms are usually disposed on the top surface and the bottom surface of the fixing module and the removable module respectively to provide suitable fixing and shock absorption for the hard disk and the removable module.
However, the horizontal residual space of the server rack is useless when the sliding mechanism is disposed on the top surface and the bottom surface of the removable module. Further, the thickness of the removable module is increased so that the total quantity of the hard disks and the removable module, which can be installed in the server rack, is reduced in a thickness direction.
However, if the sliding mechanisms are disposed on sidewalls of the removable module, the quantity of the hard disks and the removable modules, which can be installed in the server rack, is about only three in the horizontal width direction. Therefore, the space of the server rack is wasted, and especially in the horizontal width direction.
Hence, the conventional removable modules installed in the server rack cannot fully utilize the space of the server rack. Some space of the server rack is wasted, and the office space occupied by computer servers is therefore increased.